Flame-resistant organic textiles through treatment with halogen containing soluble methylol phosphine adducts

ABSTRACT

Soluble methylol phosphine adducts which contain halogen atoms attached to aromatic carbon atoms are prepared by reacting tris(hydroxymethyl)phosphine with halogen substituted phenols which contain one or more hydrogens ortho or para to the phenolic hydroxyl group. These adducts are convenient and useful for (a) the preparation of flame-resistant polymers and (b) the preparation of flame- and glow-resistant organic fibrous materials and flame-, glow-, wrinkle-, and shrink-resistant woven and knit textiles wich contain about 25 percent or more cellulosic fibers.

United States Patent 1191 Daigle et al.

Inventors: Donald J. Daigle, New Orleans;

Wilson A. Reeves; George L. Drake, Jr., both of Metairie, all of La.

The United States of America as represented by the Secretary of Agriculture, Washington, DC.

Filed: Dec. 15, 1972 Appl. No.: 315,753

Related U.S. Application Data Division of Ser. No. 141,447, May 7, 1971.

U.S. Cl. 260/47 P, 8/182, 117/136,

260/58, 260/DIG. 24 Int. Cl C08g 33/16 Field of Search 260/47 P Assignee:

References Cited UNITED STATES PATENTS 8/1958 Reeves et al 260/47 1 June 25, 1974 2,995,551 8/1961 Reuter et al. 260/249.6 3,619,113 9/1971 Stockel et a1. 8/1163 FOREIGN PATENTS OR APPLICATIONS 5,476 2/1971 Japan 197,178 5/1967 U.S.S.R.

Primary Examiner-Melvin Goldstein Attorney, Agent, or Firm-M. Howard Silverstein [5 7] ABSTRACT Soluble methylol phosphine adducts which contain halogen atoms attached to aromatic carbon atoms are prepared by reacting tris(hydroxymethyl)phosphine with halogen substituted phenols which contain one or more hydrogens ortho or para to the phenolic hydroxyl group. These adducts are convenient and useful for (a) the preparation of flame-resistant polymers and (b) the preparation of flameand glow-resistant organic fibrous materials and flame-, glow-, wrinkle-, and shrink-resistant woven and knit textiles wich contain about 25 percent or more cellulosic fibers.

2 Claims, No Drawings FLAME-RESISTANT ORGANIC TEXTILIB THROUGH TREATMENT WITH HALOGEN CONTAINING SOLUBLE METHYLOL PHOSPHINE ADDUCTS A non-exclusive, irrevocable, royalty-free license in the invention herein described, throughout the world for all purposes of the United States Government, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.

This is a division of application Ser. No. 141,447, filed May 7, 1971.

This invention relates to new halogen and phosphorus containing compounds; to halogen, phosphorus, and nitrogen containing polymers; and to processes for their use in the production of flame-resistant organic fibrous material. More specifically, it deals with a method of producing halogen containing soluble methylol phosphine adducts and the use of these to produce insoluble polymers and flame-resistant organic fibrous products through reaction of the adduct with nitrogenous compounds.

As employed throughout the specifications and claims of this invention, the term THP refers to the compound tris(hydroxymethyl)phosphine. The term halogen containing methylol phosphine adduct refers to soluble compounds produced by reacting THP with certain halogen containing phenolic compounds.

Copending application Ser. No. 141,356 by Daigle, Reeves, and Drake filed May 7, 1971 relates to the production and use of polymers made by reacting THP with hydroxy benzenes of the group consisting of phenol halo hydroxyl, and alkyl substituted phenols in which hydrogen atoms are attached to at least two ring carbon atoms which are ortho or para to a hydroxyl group.

Copending application Ser. No. 141,446 by Donaldson, Daigle, Reeves, Drake and Beninate, filed May 7, 1971, and now U.S. Pat. No. 3,734,684 relates to soluble methylol phosphine adducts prepared by reacting THP with a monomeric nitrogenous compound which contains at least one member of the group consisting of hydrogen atoms and methylol radicals attached to trivalent nitrogen atoms.

A primary object of the present invention is to provide soluble methylol phosphine adducts which contain halogen atoms attached to aromatic carbon atoms which adducts are capable of further reaction with certain nitrogenous agents to produce therrnosetting flame-resistant polymers and flame-resistant organic fibrous materials.

We have now discovered that THP reacts with monomeric halogen containing phenolic compounds which contain one or more hydrogen atoms attached to ring carbons at ortho and para positions to the phenolic group to produce soluble halogen containing methylol phosphine adducts. We have also discovered that these adducts can be further reacted with nitrogenous compounds which contain at least two members of the group hydrogen atoms and methylol radicals attached to trivalent nitrogen to produce flame-resistant polymers and flameand wrinkle-resistant textile products.

More specifically, the products and processes of our invention may be described as follows: (I) Soluble halogen containing methylol phosphine adducts are made in solution which have a pH from about 7 to 8 reacting THP with an essentially monomeric halogenated phenol which has at least one hydrogen attached to a ring carbon, ortho or para to the phenolic hydroxyl group. In order to make the soluble and useful adducts of this invention, there must be an excess of methylol phosphorus radicals (P CH OI-l) in the adduct, For purposes of the reaction, THP is trifunctional; the functionality of the halogenated phenol is determined by the number of hydrogens attached to aromatic carbons ortho or para to the phenolic OH group. The adducts of this invention are essentially materials which contain the structures of the group consisting of (HOCHl)mP CH;

where m and n are integers of 1 or 2 and the sum of m n is 3. (2) To produce thermosetting polymers in ac- 'cordance with this invention the halogen containing methylol phosphine adduct is reacted with a nitrogenous compound containing at least two members of the group consisting of hydrogen atoms and methylol radicals attached to trivalent nitrogen atoms. The-reaction is carried out by dissolving the halogen containing methylol phosphine adduct and the nitrogenous compound in a suitable medium and then heating as needed until a viscous solution and finally a solid polymer is produced. Polymers produced by this process are insoluble, thermosetting, and flame resistant. The polymers contain a reoccurring trimethylene phosphorus radical P(CH which can be oxidized to a trimethylene phosphine oxide structure OP(CI-l (3) To produce flame resistant organic textiles by a heat cure process the textile structure is wetted with a solution containing the methylol phosphorus adduct and a nitrogenous compound containing at least two members of the group consisting of hydrogen atoms and methylol radicals attached to trivalent nitrogen atoms, then drying and heating the textile at a temperature ranging from about 1 10 to C. fora period of time necessary to promote copolymerization of the methylol phosphine adduct and the nitrogenous agent within or on the textile structure. (4) To produce flame resistant organic textiles by an ammonia cure process, the textile structure is wetted with a solution containing the methylol phosphine adduct then the textile is dried and finally the dried textile is exposed to ammonia or amine gas. The amount of ammonia or amine applied to the dried textile is sufficient to react with substantially all of the P methylol radicals. One ammonia atom is capable of reacting with three P methylol radicals. The resulting product is insoluble in essentially all solvents and the flame resistant product formed in the textile is resistant to laundering and drycleaning.

l-lalophenolic compounds suitable for use in making soluble adducts of this invention include ortho halophenol, meta halophenol, para halophenol, ortho halophenetole, halophenylphenol, and haloresorcinols. The primary requirement for the halophenol is that it contain at least one hydrogen attached to a ring carbon atom which is ortho or para to a phenolic hydroxyl group. The proper molar ratios of the THP and the halophenolic compound to be used in making soluble adducts is such that the number of methylol phosphorus radicals is greater than the number of hydrogens attached to ring carbons ortho or para to phenolic hydroxyl groups. Preferably one phenolic molecule will be reacted with one THP molecule.

Solvents suitable for use in preparing the methylol phosphine adducts of this invention include dimethylformamide, alcohols such as methanol, ethanol, and isopropanol, and water and'mixtures of these compounds. The amount of solvent can be varied as desired. The adducts are used in solution, therefore, it is not necessary to isolate them. Catalysts are not necessary for conducting this reaction. However, it is particularly desirable to maintain pH of the system from about 7 to about 8.

Suitable'nitrogenous compounds for use with the halogen containing methylol phosphine adducts in the production of thermosetting polymers include virtually any soluble nitrogenous compound containing at least two members of the group consisting of hydrogen atoms and methylol radicals attached to trivalent nitrogen atoms. Examples of suitable amides include urea, thiourea, melamine, cyanamide, ethyleneurea, propyleneurea, dicyandiamide, hydroxyethylcarbamate, octadecamide, acrylamide, amino acids, methylol and alkylated methylol derivatives of these amides. Examples of suitable amines include ethylamine, methylamine, ethylenediamine, ammonia, analine, and cetylamine. Mixtures of these amides and amines can suitably be employed. Thermosetting polymers are principally prepared by agitating a mixture of the adduct and the nitrogen compound or compounds in a solvent system while heating until copolymerization occurs. The preferred relative amounts of methylol phosphine adduct and nitrogen compounds used to copolymerize can be calculated by conventional methods for condensation polymerization reactions assuming that the functionality of the adduct equals the number of methylol phosphorus radicals on the adduct and that the functionality of the nitrogenous agent is equal to the sum of the number of hydrogens and methylol radicals attached to trivalent nitrogen. Useful products may contain as little as about one mole of the soluble adduct per ten moles of nitrogenous compounds. The use of small quantities of the adduct with large quantities of the nitrogenous compound is made practical when the nitrogenous compound contains N-methylol radicals (NCH OH) which permit the compounds to form condensation polymers even in the absence of the soluble methylol phosphine adduct. The maximum proportions of the soluble adduct that may be used with a nitrogenous compound for the production of useful polymers is about one mole of the adduct per mole of the nitrogenous compound.

In the production of flame-resistant organic fibrous materials by a heat cure process, the fibrous structure is wetted with a solution containing the soluble adduct and the nitrogenous agent; it is then passed through squeeze rolls to remove excess liquid. The structure is then dried and heated from about 1 10 to about 160 C. The pH of this treating solution may range from about 3 up to about 7.5. It is generally desirable for the treating solution to contain an acid producing catalyst such as zinc nitrate, magnesium chloride, hydrochloric acid, ammonium chloride, or a mixture of magnesium chloride and an organic acid such as citric acid. The amount of acid catalyst needed may be varied from about 0.5 percent up to about 3 percent based on the weight of the solution. The concentration of the adduct and the nitrogenous agent in the treating solution can be varied depending upon the amount of flame resistance to be imparted to the organic fibrous structure. Even one or two percent of the adduct and nitrogenous agent produces marked changes in the burning characteristics of the treated textile structure. Where complete flame resistance is to be contributed, about 10 to 20 weight percent must be applied to the textile structure. r

In the treatment of organic fibrous structures by the ammonia cure process, the textile structure is wetted with a solution of halogen containing soluble methylol phosphine adduct, then the fabric is dried at a temperature ranging between about C. and C. Finally, the fabric structure is exposed to ammonia gas for a few seconds, generally from two to fifteen seconds. The time of the exposure to ammonia is not so important as the amount of ammonia applied to the fabric. The amount of ammonia applied should be adequate to react with essentially all of the P methylol radicals. If desired, one can complete the insolubilization of the adduct by first exposing the dry fabric to NH, gas for about 2 to 10 seconds then passing the fabric through a dilute solution of ammonium hydroxide. However, this order of treatment cannot be reversed. While ammonia is the most convenient nitrogenous gaseous product for use in this chemical cure, other amines may also be used, particularly methylamine and ethylamine. A preferred procedure for treating the textile structure with the amine is to force ammonia gas or methylamine through the textile structure. In this manner, reaction can be completed within one to three seconds.

Virtually any fibrous organic product capable of being impregnated with the soluble adduct can be made flame resistant by use of this invention. Textiles suitable for use in this invention are woven, knit, or nonwoven structures. For best results, the textile structure should contain at least about 25 percent of a cellulosic fiber. Cellulosic fibers suitable for use in this invention include, cotton, rayon, ramie, flax, and the like fibers. Various noncellulosic natural fibers can also be used in this invention, such as wool and mohair. Noncellulosic synthetic fibers suitable for use in this invention along with a cellulosic fiber are polyesters, nylons, acrylics, polyvinylchloride, and the like fibers. When cellulosic fibers are blended with flammable noncellulosic fibers it is preferable to have about 50 percent or more cellulosic fiber in the blend structure.

The following example is illustrative of the invention:

EXAMPLE 1 Soluble methylol phosphine adducts containing phosphorus and halogen were prepared by reacting THP (melting point about 58 C.) with a halogenated phenol as exemplified in Table I. These stable adducts were put into solution with an amine or amide to produce copolymer solutions as shown in Table II. One of the adducts was put in fabric by a padding process, then the fabric was dried and exposed to NH;, gas for a few seconds to insolubilize the adduct in or on the fabric as shown in Table III. Aliquots of the copolymer solutions from Table II were also applied to fabric by the padding technique. These fabrics were either heated at elevated temperatures or exposed to NH; gas to form insoluble 3,819,580 4 5 V 6 flame retardants in or on the cotton as described in tions of Table II were polymerized as described in Table III. Parts of each fabric from Table III were laun- Table IV to produce insoluble thermosetting flame .redered then examined. All samples exhibited a signifi- Sistant products. 1 cant degree of flame resistance. The copolymer solu- TABLE I PREPARATION OF SOLUBLE METHYLOL PHOSPHINE ADDUCTS CONTAINING HALOGEN AND PHOSPHORUS Adduct Solution I Conditions for Designation Reagents in Solution the Reaction 77-l 4L3 g (.33 mole) THP Heated at 80 C. for

58 g (.33 mole) p-Bromophenol min. then cooled.

150 g Iospropyl alcohol (about solids in solution) 772 41.3 g (.33 mole) THP Heated at C. for 29 g (.l mole) p-Bromophenol 30 min. then cooled.

l 10 g lsopropyl alcohol (about 39% solids in solution) TABLE II PREPARATION OF COPOLYMER SOLUTIONS FROM SOLUBLE ADDUCT AND AMIDES OR AMINES .08 mole THP .08 mole p-Bromophenol 37 g Iospropyl alcohol 77-4 of adduct 77-l 7.5 g of 50% aqueous cyanamide which contains: (0.I mole) .08 mole THP .08- mole p-Bromophenol 37 g Isopropyl alcohol 77-5 A; of adduct 77-2 5.4 g urea in 7 ml H 0 (.09 mole) which contains:

.08 mole THP .04 mole p-Bromophenol 28 g Isopropyl alcohol 77-6 A of adduct 77-2 56.6 g of 30% aqueous methylolwhich contains: urea (.1 mole) .08 mole THP (The methylolurea contained on .04 mole p-Bromophenol the average 1.5 methylol groups 28 g Isopropyl alcohol per urea molecule.)

TABLE III PREPARATION OF FLAME RESISTANT TEXTILES THROUGH USE OF SOLUBLE HALOGEN CONTAINING METHYLOL PHOSPHINE ADDUCTS Adduct or Conditions Approximate v Properties of Treated Fabric Copolymer for Depositing Add-On of Solution Insoluble Retardant Match After- Fabric Treated Applied to Polymer in After Washing Test glow Fabric Fabric the Treated Hand Strength Color Angle sec.

Textile 50/50 Polyester/Cotton Blend 77-4 NH gas l7.l Good Good White 180 2 for 6 min. (Totton Sheeting 77-5 Heat, [50 9.4 Good Good White 2 3 min. Cotton Sheeting 77-6 Heat. I50 I25 Good Good White 110 2 3 min. Cotton Sheeting 77-2 NH gas Good Good White 2 for l min.

TABLE IV PREPARATION OF INSOLUBLE THERMOSETTING FLAME AND GLOW RESISTANT POLYMERS AMlNES OR AMlDES Time Required to Produce Insoluble Product Copolymer Solution Used Temperature Reaction Nature of Polymer o THROUGH USE OF SOLUBLE ADDUCTS AND 77-3 25 20 min.

acid and alkali.

Formed within 20 min.

at l C.

White, insoluble in H O,

Flame resistant and forms black char.

77-4 I00 min.

Yellow, hard, insoluble in H O, acid and alkali. Formed by heating on steam cone 20 min.

Flame resistant and forms black char 77-S 150 I0 min.

hard.

Yellow, insoluble in H O,

Flame resistant and forms black char.

77-6 I50 l0 min.

White, insoluble in F1 0 Flame resistant and forms black char.

We claim:

1. A thermosetting flame resistant polymer produced by heating a halogen-containing phenolic methylol phosphine adduct of the formula (HO CH1) m P CH 2. A process for producing flame resistant thermoset- 1 ting polymers which comprises heating a halogencontaining phenolic methylol phosphine adduct of the formula (HOCHI) m I CH2 wherein m and n are integers of l or 2, the sum of m and n is 3, and x is halogen, with a nitrogenous compound selected from the group consisting of amines,

amides and mixtures of said amides and amines. 

2. A process for producing flame resistant thermosetting polymers which comprises heating a halogen-containing phenolic methylol phosphine adduct of the formula 